"I can't even begin to touch that one, to be honest, because it's a three-year-old," she said. "I would imagine your child having cancer is devastating as a parent."

Doherty added that she could only urge the couple to "stay positive," noting: "That positivity, that outlook on life that you can get through something, it actually does get you through."

"Just trust in your doctors," she added. "Make sure you have amazing doctors, a great team, and know that organizations like the American Cancer Society [and] Stand Up to Cancer, they are doing so much good for cancer. And [there is] so much research that we have much better chances now."